Typically, taxis charge a fixed fee - often around $2 - or a percentage of the fare to cover the cost of processing payments on wireless electronic terminals.
Mr Stewart, 51, a charge nurse at Auckland City Hospital, said he used taxi services once every fortnight, and had no idea a surcharge was imposed for a card transaction.
"I never realised that. I will definitely make sure I have cash when I catch a cab again."
Another taxi user, 22-year-old student Alex De Lisle, said she was also unaware of the surcharges.
"I don't often use taxis, but I never knew they charged more for using your card.
"I find that really annoying because they are already quite dear," she said.
Despite the reaction on the street yesterday, taxi companies said most customers did not mind paying an extra fee for card transactions.
"I think it's fair to say that all taxi companies charge for credit transactions one way or another," said Taxi Federation executive director Tim Reddish.
"And that reflects the cost of installing the equipment and having the payments processed."
Harpreet Gill, of the Auckland branch of the Taxi Federation, put the average monthly cost of operating the system in a taxi at $50 to $70.
"The use of eftpos (for a taxi ride) is growing significantly despite the cost of doing it. I think generally people accept the price for the convenience."
Driver Sam Singh, of Auckland Co-op Taxis, said in his experience most customers seemed to know about the surcharge.
"It's displayed on the fare schedule. Some people ask about it, but most people know, especially our regular customers."
The 32-year-old, who has been with Auckland Co-op Taxis for five years, said his company charged a flat rate of $2.30 for eftpos and credit card payments.
Fellow driver Raymond Patel, of the Discount Taxi company, said he accepted credit card payments but did not have facilities set up for eftpos payments.
Mr Patel, who has worked for the Discount Taxi company for 12 years, said a surcharge of 10 per cent was applied to credit card payments by his company. The 50-year-old said his taxi was not set up for eftpos payment facilities because "it is expensive to keep".
He said that in his experience most people seemed to use cash, but those who did pay by credit card did not complain about the extra charge.
The survey, commissioned by public relations agency Impact PR, gauged the impact a surcharge of 3 per cent would have on shopping habits.
It found that more than 88 per cent of shoppers said they were "very likely" or "somewhat likely" to take their custom to a store that did not charge the fee.